Quote CRISPI..." . it can be difficult to be certain all this complexity is improving riding a wave,we all have differnt goals on a wave..."
Yes I've also thought about the purpose / worth / validity of foiling.
Do foils improve wave riding ? An improvement is not just bigger/ higher/ faster, improvement can also be about quality. Considering that 'improve' is up to each person to decide, I've found that foiling is a dramatically different sensation of control and speed so for me foiling is a definate improvement because it's creates a new world of interaction between rider and wave. Foiling is also an improvement in understanding, all previous surfcraft ride in or on the wave but when you're foiling it's just the foil in the water. ( most of the time) So there's an improvement in understanding more about the wave and the forces at play within the wave, it's undeniable that you have to understand more to ride a foil.

Here's the basic foil. Just 3 ply with 1 layer of 10 oz glass on both sides.

You can see that it's really low volume. One of the principles I Follow us that displacement slows a board or a foil down. The bigger the volume of the object, the greater the volume of water it needs to move away in order to move forward and thus the more power is needed to move it through the water so I've always kept the foils as thin as possible. Keeping them thin also keeps them light which is always a bonus too.

The aluminium struts are 12 inches high, in order to get the board out of the water there needs to be some distance between the board and the foil and for a flat foil that will sit about 6 inches under the surface that gives me about 6 inches of clearance above the wave. Flat or 'single level' foils are great until you get into meaty waves or tubes becuase there's a lot of speed and a lot of lift and that's when 'single level' foils can leap clear of the surface.
If you use multiple level foils like this one, you get a foil that automatically matches the amount of lift to the speed by reducing the planing area.

The board I've decided to put two pine stringers in that also double as supports where I screw the struts into the board. Using screws to connect the sections together doesn't sound ideal but it's never failed in the surf and it's easy to swap foils and struts.

I've still got to trim the stringers down before I glue it all together.

Here it is 3/4 finished,SR-72C with Hydro Gravity Drive .I think it will run very interesting lines on a wave face, it has got a bit heavy 4.5KG,but it is bullet prof
for running over slow moving water hazards like SUPs,and longboards.

Hi Brett,
I need information on surfboard performance telemetry, what is out there, I think I need a speed o meter or something to measure surface speed, there must be a small speed sensor out there. GPS is too average, like if you go forward 2ft but drop 6ft GPS can’t pick that up. You talked about board speed before, how fast is near free fall, or how fast are you going at the bottom of a free fall. I feel near free fall is the fastest a surf board can go.

Hi Chris and Bob, I had a few conversations with Terry about surfing speed and it's clear that there are two speeds, speed thru the water and speed across the land. F'instance an almost vertical drop would be a very high acceleration thought the water but a GPS wouldn't register any speed at all. Also some waves are incredibly fast down the line but because they wrap around a point a GPS might even record a negative speed.
So in the end speed through the water is the only real consideration becuase that's the speed that relates to flow, lift and drag.
I used to wear a GPS device for about 3 years that gave accurate but averaged readings and on every surf I recorded the size of the waves and the speeds attained and it was a good reference point for my own observations. In the end I was more interested in the numbers but it also became clear that there is a logical top speed for every wave. If the breaking part of the wave is travelling at say...20 kph you can't hit 40 , 50 or 60 kph for more than a second or 2 because you would logically outrun the wave, lose speed on the flat water and then slow down until the wave caught up again.
On a fast and vertical wall you could reach a speed higher than the breaking wave by pumping along the face but prone boards have no means on adding energy to pump the board like a shortboarder can.
The whole 'speed' issue because something that only mattered if you could measure it and for me it was interesting to quantify the speeds but it also became something that ultimately didn't matter any more than I wanted it to.
Follow the speed and the numbers like I did becuase you learn so much more but I found that speed isn't the most important thing.

Hi Bob ,Brett
I don’t want to sound egotistical going on about how fast my board s are, but it seems quantifying incremental changes in surf craft is very difficult. In cars, boats and planes you can read a spec sheet and by glancing at the HP and weight you can tell how fast it will be. Surf craft performance improvement seems to be personal intuition, it feels faster or it feels like it turns better. It is a very unscientific approach to performance improvements. I think GPS on a wave pool may be one solution with consistent wave size, power and length, but they can be hard to access. I am looking at may be converting a water proof bike Speedo, with a trailing propeller pickup head? So i can check between boards easily.

The glassing is finished, now the most difficult decision to make what colour and pattern? I am not certain about fitting fins yet. It has lost the organic look of pectoral fins and is more aircraft looking

The thin-ness of the foil probably makes it impossible, but if there was a way to install a fin/fins that were movable you could experiment with number/position. Your previous vboards seem to have a centre fin - have you experimented with fin location much?

Hi Bob,
I have used a fin for so long now I can’t remember how they run without, but I can add one later if necessary, I see lot of people on this forum run finless and they seem to make it work. The anticipation to get this board in the water is building.

Bob,
The anhedral wing and the tail rail should give sufficient hold, if it doesn’t hold I will make a slip on wing fence, I think keeping it as clean as possible is important, there is already a lot of stuff hanging in the water